Earnings Per Share, Pro Forma Earnings Per Share Reconciliation (Details) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended								12 Months Ended
	Jan. 27, 2021	Dec. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares
Net income attributable to Amphenol Corporation shareholders | $		$ 357.0	$ 346.6	$ 257.7	$ 242.1	$ 318.7	$ 280.3	$ 288.4	$ 267.5	$ 1,203.4	$ 1,155.0	$ 1,205.0
Effect of dilutive stock options (in shares)										9.5	10.4	11.4
Pro Forma [Member]
Net income attributable to Amphenol Corporation shareholders | $										$ 1,203.4	$ 1,155.0	$ 1,205.0
Basic weighted average common shares outstanding										596.1	595.0	602.4
Effect of dilutive stock options (in shares)										18.9	20.9	22.8
Diluted weighted average common shares outstanding										615.0	615.9	625.2
Pro Forma Earnings per share attributable to Amphenol Corporation shareholders
Basic | $ / shares										$ 2.02	$ 1.94	$ 2.00
Diluted | $ / shares										$ 1.96	$ 1.88	$ 1.93
Subsequent Event
Pro Forma Earnings per share attributable to Amphenol Corporation shareholders
Stock split conversion ratio	2